The present invention relates to a drilling system including a drilling machine and a compressor to be connected to the drilling machine. The present invention also relates to a compressor used for a power tool such as the drilling machine.
A drilling machine for drilling holes into a structure such as a concrete wall or the like is known as disclosed in Laid-open Japanese Utility Model Application Publication No. S62-201642. The drilling machine disclosed in the JP publication includes a main body and a drill bit extending from the main body. The drill bit has a discharge port and an air passageway connected to the discharge port. The main body is also formed with an air passageway connected to the air passageway of the drill bit. The discharge port is formed in the vicinity of a cutting edge for ejecting compressed air from the cutting edge. The air passageway in the main body of the drill machine is connected to an air outlet port of a compressor, so that the compressed air is discharged into the main body and is ejected out of the discharge port of the drill bit. Accordingly, the drill bit as well as the drilled target are cooled, and cut-out concrete dust can be discharged out of a drilled hole.
In the conventional drilling system, the rotation of a motor for rotating the drill bit and delivery of the compressed air from the compressor are not linked with each other. Therefore, an operator of the machine must adjust an air-valve provided at the main body or at the compressor in order to deliver the compressed air. Thus complicating operation results. Further, compressed air may be discharged from the discharge port even under the condition that the drilling machine has not been started up. Thus, the compressed air has been consumed uselessly. To this effect, a large capacity compressor capable of generating greater amount of compressed air must be required taking the excessive consumption of the compressed air into consideration.
Further, in a construction site or the like in which the drilling machine is frequently used, a temporary power source is set up for allowing electric tools to be used. Since the electric power supplied from the temporary power source is lower than that supplied from a permanent power source, a frequent use of electric tools and the like that consume a large electric power may cause an overcurrent protector to be activated to render the temporary power source inoperative.
In the drilling system, each of the drilling machine and the compressor provides a driving unit requiring great amount of electric power. Thus, a simultaneous use of the drilling machine and compressor may cause the overcurrent protector to be activated to stop the supply of the power during drilling work. Further, if two driving units are operated at the same time, operational sound becomes noisy.
Further, in the case where the drilling system is used to drill holes for curtain wall anchors, holes are pierced in a sequential manner while the operator moves along the wall surface of a building. In such a case, the drilling system must also be moved. A large-sized compressor involves additional work when the compressor needs to be moved to lower workability.
Furthermore, if the drilling machine and the compressor are respectively connected to the temporary power source by means of respective power cords, a workable area is reduced to the length of the shorter power cord. Accordingly, the operator can work only the area dependent on the shorter power cord. In order to enlarge the workable area, a position of the temporary power source needs to be frequently changed. When the longer power cords are used, a workable area centered on one power source can be enlarged. However, cable handling becomes difficult to lower workability.